[MUSIC] Hello student, welcome back. We're going to continue to talk about food. And I'm going to cover about enjoyment of food and how are we going to define whether the food tastes good or bad. And what kind of parameter defines it? Now, in fact, there are a few things I want to talk about. First of all, I want to talk about when the food comes to our body. What are they? And how are they being perceived? And most of the time, in fact, these are the chemical that we take into our body. And in fact, it's going to trigger a whole bunch of physiological response, which involves hormone. And they would regulate how we feel and whether we want to have more, we don't want to have more. Of course, all this food, when it come in front of us, it is because of how they look, how they taste, how they smell. So therefore there's a lot of sensory input. And so, for that, we need to look at how these sensory input is being perceived by us and how it's going to affect the quality of this food. And finally, we want to talk about how this so called sensory-specific satiety, when we are constantly being stimulated by the same sense. How do we feel? And whether we get tired of them, or even though that we love this kind of food. But then we can continue to eat them again and again, even though we are full. Now having that in mind, I want to highlight a few other factors, which is affecting how we perceive the quality of food. In fact, a lot of time when we are eating, the surrounding atmosphere makes a lot of difference. When you're in a very romantic restaurant or whether you're eating with your family. The mood, what kind of mood you are in, in fact affect how you taste the food. Sometimes the environment, whether you're outdoor, indoor, the dishes when it has been put on the table, whether they give it a very good name. Reminding you some of your memory, that is going to change your perception of the quality. And, of course, sometimes we have personal experience, and some of our responses to a particular flavor. That would all influence how we perceive food being good or bad. Now, we can ask ourself, why do we want to have food? Why do we want eating? As a biologist, a lot of times we look at this because we want to have nutrients. We eat food. What kind of food? Vegetable? Fruits? These are sweet food. And both of them, when they were taken, they'll be converted into energy. And one type of the energy, such as a mineral, amino acid, vitamin or glucose. These are all very important, they allowed us to be incorporated, having all these nutrients for us to mature, to grow as an individual. But let me remind you, most of the time these days, when we're eating, it's simply not because of all this calculation of how much nutrients are there. It's simply because we are hungry, when you're hungry, you eat. And sometimes even though we're not hungry, simply because we like to eat. Something that we like so much that we want to keep on eating it, it is called craving. Now, that defines at a stage when or why we want to have food. Now, let them come to the point of hunger. We say that a lot of time when you're hungry, you want to eat food. But what is controlling it? As I pointed out earlier a lot of it is because of our biological response, it's because of these logical states because we don't have enough energy. We want nutrients. So therefore, we want to eat so that we can recapture some of these nutrients to allow us to function normally. But as I pointed out, a lot of time, it's the psychological state, the social state. How we're interacting with the environment. All this affects us. So therefore, I want you to stop thinking about the reason why we eat is because of all this integral response in our brain. And that tells us that we want to eat something. And sometimes we enjoy eating, not necessarily because we are eating the material, the food by itself It's because we like the feeling of anticipating that some food will be available very soon. Now, so in the next section, what I'm going to tell you is that I want to dissect this process one at a time. We're going to address how the endocrine system, how our neural system, how we feel the sensory specific satiety, when you are stimulated by the same food again and again. Whether you feel full or you become tired of it. And finally, why sometimes even though we're not hungry, we still want to eat? Why we have this craving behavior? So we will address it in a moment.